Cosworth plans to unveil the car at the Geneva Motor Show in March. Until then, all we have is the above shot and a cryptic teaser:

Two of the biggest names in automotive performance have come together to work on a special one-off project, and the result promises to be truly staggering. Subaru UK and Cosworth have enhanced the performance, handling and styling of the acclaimed Impreza STI, creating a car that will raise the bar for all-wheel-drive, high-performance motoring.